METHOD FOR COATING MICRO-PARTICLES WITH ZIRCONIUM CARBIDE OR ZIRCONIUM-CARBIDE-CARBON ALLOY

摘要

1470227 Nuclear fuel JAPAN ATOMIC ENERGY RESEARCH INSTITUTE 21 June 1974 [22 June 1973] 27578/74 Heading G6C [Also in Division C7] Microparticles of nuclear fuel, e.g. carbides and oxides of U and Th are coated with ZrC or a ZrC-C alloy by pyrolyzing in a fluidized bed of the particles in the presence of H 2 a mixture of a hydrocarbon and a vapour formed by reacting Zr sponge with Br vapour. As shown in the drawing the microparticles are heated in tube 3 containing nozzles 5 in furnace 1 to 1100-1400‹ C. and fluidized with an inert gas, e.g. argon and H 2 which flows through the annulus between an inner tube 4 and the tube 3. Zr sponge in the inner tube 4 is heated to 400- 800‹ C. and Br and argon are passed through the heated sponge to form ZrBr 4 vapour which is passed through the fluidized bed while a hydrocarbon gas, e.g. CH 4 is also passed through the bed with the fluidizing gas.